Trench warfare is a type of land warfare using occupied lines largely comprising military trenches, in which troops are well-protected from the enemy's small arms fire and are substantially sheltered from artillery. Trench warfare became archetypically associated with World War I (1914–1918), when the Race to the Sea rapidly expanded trench use on the Western Front starting in September 1914.[1]
Trench warfare proliferated when a revolutionin firepower was not matched by similar advances in mobility, resulting in a gruelling form of warfare in which the defender held the advantage.[2] On the Western Front in 1914–1918, both sides constructed elaborate trench, underground, and dugout systems opposing each other along a front, protected from assault by barbed wire. The area between opposing trench lines (known as "no man's land") was fully exposed to artillery fire from both sides. Attacks, even if successful, often sustained severe casualties.
The development of armoured warfare and combined arms tactics permitted static lines to be bypassed and defeated, leading to the decline of trench warfare after the war.
Following World War I, "trench warfare" became a byword for stalemate, attrition, sieges, and futility in conflict.[3]
Precursors
Field works are as old as armies. Roman legions, when in the presence of an enemy, entrenched camps nightly when on the move.[4]
Trench warfare was also documented during the defense of Medina in a siege known as the Battle of the Trench (627 AD). The architect of the plan was Salman the Persian who suggested digging a trench to defend Medina.
In early modern warfare troops used field works to block possible lines of advance.[5]Examples include the Lines of Stollhofen, built at the start of the War of the Spanish Succession of 1702–1714,[6] the Lines of Weissenburg built under the orders of the Duke of Villars in 1706,[7] the Lines of Ne Plus Ultra during the winter of 1710–1711,[5] and the Lines of Torres Vedras in 1809 and 1810.[4]
In the New Zealand Wars (1845–1872), the Maori developed elaborate trench and bunkersystems as part of fortified areas known as pā, employing them successfully as early as the 1840s to withstand British artillery bombardments.[8][9] According to one British observer, "the fence round the pa is covered between every paling with loose bunches of flax, against which the bullets fall and drop; in the night they repair every hole made by the guns".[10] These systems included firing trenches, communication trenches, tunnels, and anti-artillery bunkers. British casualty rates of up to 45 percent, such as at Gate Pain 1864 and the Battle of Ohaeawai in 1845, suggested that contemporary weaponry, such as muskets and cannon, proved insufficient to dislodge defenders from a trench system.[11]There has been an academic debate surrounding this since the 1980s, when in his book The New Zealand Wars, historian James Belich claimed that Northern Māori had effectively invented trench warfare during the first stages of the New Zealand Wars. However, this has been criticised by some other academics, with Gavin McLean noting that while the Māori had certainly adapted pā to suit contemporary weaponry, many historians have dismissed Belich's claim as "baseless... revisionism".[12]
The Crimean War (1853–1856) saw "massive trench works and trench warfare",[13] even though "the modernity of the trench war was not immediately apparent to the contemporaries".[14]
Union and Confederate armies employed field works and extensive trench systems in the American Civil War (1861–1865) — most notably in the sieges of Vicksburg (1863) and Petersburg (1864–1865), the latter of which saw the first use by the Union Army of the rapid-fire Gatling gun,[15] the important precursor to modern-day machine guns. Trenches were also utilized in the Paraguayan War (which started in 1864), the Second Anglo-Boer War (1899–1902), and the Russo-Japanese War (1904–1905).[citation needed]
Adoption
Although technology had dramatically changed the nature of warfare by 1914, the armies of the major combatants had not fully absorbed the implications. Fundamentally, as the range and rate of fire of rifled small-arms increased, a defender shielded from enemy fire (in a trench, at a house window, behind a large rock, or behind other cover) was often able to kill several approaching foes before they closed with his position. Attacks across open ground became even more dangerous after the introduction of rapid-firing artillery, exemplified by the "French 75", and high explosive fragmentation rounds. The increases in firepower had outstripped the ability of infantry (or even cavalry) to cover the ground between firing lines, and the ability of armour to withstand fire. It would take a revolution in mobility to change that.[16]
The French and German armies adopted different tactical doctrines: the French relied on the attack with speed and surprise, and the Germans relied on firepower, investing heavily in howitzers and machine guns. The British lacked an official tactical doctrine, with an officer corps that rejected theory in favour of pragmatism.[17]
While the armies expected to use entrenchments and cover, they did not allow for the effect of defences in depth. They required a deliberate approach to seizing positions from which fire support could be given for the next phase of the attack, rather than a rapid move to break the enemy's line.[18] It was assumed that artillery could still destroy entrenched troops, or at least suppress them sufficiently for friendly infantry and cavalry to manoeuvre.[19]
Digging-in when defending a position was a standard practice by the start of WWI. To attack frontally was to court crippling losses, so an outflanking operation was the preferred method of attack against an entrenched enemy. After the Battle of the Aisne in September 1914, an extended series of attempted flanking moves, and matching extensions to the fortified defensive lines, developed into the "race to the sea", by the end of which German and Allied armies had produced a matched pair of trench lines from the Swiss border in the south to the North Seacoast of Belgium.
By the end of October 1914, the whole front in Belgium and France had solidified into lines of trenches, which lasted until the last weeks of the war. Mass infantry assaults were futile in the face of artillery fire, as well as rapid rifle and machine-gun fire. Both sides concentrated on breaking up enemy attacks and on protecting their own troops by digging deep into the ground.[20] After the buildup of forces in 1915, the Western Front became a stalemated struggle between equals, to be decided by attrition. Frontal assaults, and their associated casualties, became inevitable because the continuous trench lines had no open flanks. Casualties of the defenders matched those of the attackers, as vast reserves were expended in costly counter-attacks or exposed to the attacker's massed artillery. There were periods in which rigid trench warfare broke down, such as during the Battle of the Somme, but the lines never moved very far. The war would be won by the side that was able to commit the last reserves to the Western Front. Trench warfare prevailed on the Western Front until the Germans launched their Spring Offensive on 21 March 1918.[21] Trench warfare also took place on other fronts, including in Italy and at Gallipoli.
Armies were also limited by logistics. The heavy use of artillery meant that ammunition expenditure was far higher in WWI than in any previous conflict. Horses and carts were insufficient for transporting large quantities over long distances, so armies had trouble moving far from railheads. This greatly slowed advances, making it impossible for either side to achieve a breakthrough that would change the war. This situation would only be altered in WWII with greater use of motorized vehicles.[22][23]
Construction
Early World War I trenches were simple. They lacked traverses, and according to pre-war doctrine were to be packed with men fighting shoulder to shoulder. This doctrine led to heavy casualties from artillery fire. This vulnerability, and the length of the front to be defended, soon led to front line trenches being held by fewer men. The defenders augmented the trenches themselves with barbed wire strung in front to impede movement; wiring parties went out every night to repair and improve these forward defences.[25]
The small, improvised trenches of the first few months grew deeper and more complex, gradually becoming vast areas of interlocking defensive works. They resisted both artillery bombardment and mass infantry assault. Shell-proof dugouts became a high priority.[26]
A well-developed trench had to be at least 2.5 m (8 ft) deep to allow men to walk upright and still be protected.
There were three standard ways to dig a trench: entrenching, sapping, and tunnelling. Entrenching, where a man would stand on the surface and dig downwards, was most efficient, as it allowed a large digging party to dig the full length of the trench simultaneously. However, entrenching left the diggers exposed above ground and hence could only be carried out when free of observation, such as in a rear area or at night. Sapping involved extending the trench by digging away at the end face. The diggers were not exposed, but only one or two men could work on the trench at a time. Tunnelling was like sapping except that a "roof" of soil was left in place while the trench line was established and then removed when the trench was ready to be occupied. The guidelines for British trench construction stated that it would take 450 men 6 hours at night to complete 250 m (270 yd) of front-line trench system. Thereafter, the trench would require constant maintenance to prevent deterioration caused by weather or shelling.
Trenchmen were a specialized unit of trench excavators and repairmen. They usually dug or repaired in groups of four with an escort of two armed soldiers. Trenchmen were armed with one 1911 semi-automatic pistol, and were only utilized when either a new trench needed to be dug or expanded quickly, or when a trench was destroyed by artillery fire. Trenchmen were trained to dig with incredible speed; in a dig of three to six hours they could accomplish what would take a normal group of frontline infantry soldiers around two days. Trenchmen were usually looked down upon by fellow soldiers because they did not fight. They were usually called cowards because if they were attacked while digging, they would abandon the post and flee to safety. They were instructed to do this though because through the war there were only around 1,100 trained trenchmen. They were highly valued only by officers higher on the chain of command.[citation needed]
Components
The banked earth on the lip of the trench facing the enemy was called the parapet and had a fire step. The embanked rear lip of the trench was called the parados, which protected the soldier's back from shells falling behind the trench. The sides of the trench were often revetted with sandbags, wire mesh, wooden frames and sometimes roofs. The floor of the trench was usually covered by wooden duckboards. In later designs the floor might be raised on a wooden frame to provide a drainage channel underneath.
The static movement of trench warfare and a need for protection from snipers created a requirement for loopholes both for discharging firearms and for observation.[27]Often a steel plate was used with a "key hole", which had a rotating piece to cover the loophole when not in use.[27] German snipers used armour-piercing bullets that allowed them to penetrate loopholes. Another means to see over the parapet was the trench periscope – in its simplest form, just a stick with two angled pieces of mirror at the top and bottom. A number of armies made use of the periscope rifle, which enabled soldiers to snipe at the enemy without exposing themselves over the parapet, although at the cost of reduced shooting accuracy. The device is most associated with Australian and New Zealand troops at Gallipoli, where the Turksheld the high ground.
Dugouts of varying degrees of comfort were built in the rear of the support trench. British dugouts were usually 2.5 to 5 m (8 to 16 ft) deep. The Germans, who had based their knowledge on studies of the Russo-Japanese War,[28] made something of a science out of designing and constructing defensive works. They used reinforced concrete to construct deep, shell-proof, ventilated dugouts, as well as strategic strongpoints. German dugouts were typically much deeper, usually a minimum of 4 m (12 ft) deep and sometimes dug three stories down, with concrete staircases to reach the upper levels.[citation needed]
Layout
Trenches were never straight but were dug in a zigzagging or stepped pattern, with all straight sections generally kept less than a dozen meters (yards). Later, this evolved to have the combat trenches broken into distinct fire bays connected by traverses. While this isolated the view of friendly soldiers along their own trench, this ensured the entire trench could not be enfiladed if the enemy gained access at any one point; or if a bomb, grenade, or shell landed in the trench, the blast could not travel far.
Very early in the war, British defensive doctrine suggested a main trench system of three parallel lines, interconnected by communications trenches. The point at which a communications trench intersected the front trench was of critical importance, and it was usually heavily fortified. The front trench was lightly garrisoned and typically occupied in force only during "stand to" at dawn and dusk. Between 65 and 90 m (70 and 100 yd) behind the front trench was located the support (or "travel") trench, to which the garrison would retreat when the front trench was bombarded.
Between 90 and 270 metres (100 and 300 yd) further to the rear was located the third reserve trench, where the reserve troops could amass for a counter-attack if the front trenches were captured. This defensive layout was soon rendered obsolete as the power of artillery grew; however, in certain sectors of the front, the support trench was maintained as a decoy to attract the enemy bombardment away from the front and reserve lines. Fires were lit in the support line to make it appear inhabited and any damage done immediately repaired.
Temporary trenches were also built. When a major attack was planned, assembly trenches would be dug near the front trench. These were used to provide a sheltered place for the waves of attacking troops who would follow the first waves leaving from the front trench. "Saps" were temporary, unmanned, often dead-end utility trenches dug out into no-man's land. They fulfilled a variety of purposes, such as connecting the front trench to a listening post close to the enemy wire or providing an advance "jumping-off" line for a surprise attack. When one side's front line bulged towards the opposition, a salient was formed. The concave trench line facing the salient was called a "re-entrant." Large salients were perilous for their occupants because they could be assailed from three sides.
Behind the front system of trenches there were usually at least two more partially prepared trench systems, kilometres to the rear, ready to be occupied in the event of a retreat. The Germans often prepared multiple redundant trench systems; in 1916 their Somme front featured two complete trench systems, one kilometre apart, with a third partially completed system a further kilometre behind. This duplication made a decisive breakthrough virtually impossible. In the event that a section of the first trench system was captured, a "switch" trench would be dug to connect the second trench system to the still-held section of the first.
Wire
The use of lines of barbed wire, razor wire, and other wire obstacles, in belts 15 m (49 ft) deep or more, is effective in stalling infantry traveling across the battlefield. Although the barbs or razors might cause minor injuries, the purpose was to entangle the limbs of enemy soldiers, forcing them to stop and methodically pull or work the wire off, likely taking several seconds, or even longer. This is deadly when the wire is emplaced at points of maximum exposure to concentrated enemy firepower, in plain sight of enemy fire bays and machine guns. The combination of wire and firepower was the cause of most failed attacks in trench warfare and their very high casualties. Liddell Hart identified barbed wire and the machine gun as the elements that had to be broken to regain a mobile battlefield.
A basic wire line could be created by draping several strands of barbed wire between wooden posts driven into the ground. Loose lines of wire can be more effective in entangling than tight ones, and it was common to use the coils of barbed wire as delivered only partially stretched out, called concertina wire. Placing and repairing wire in no man's land relied on stealth, usually done at night by special wiring parties, who could also be tasked with secretly sabotaging enemy wires. The screw picket, invented by the Germansand later adopted by the Allies during the war, was quieter than driving stakes. Wire often stretched the entire length of a battlefield's trench line, in multiple lines, sometimes covering a depth 30 metres (100 ft) or more.
Methods to defeat it were rudimentary. Prolonged artillery bombardment could damage them, but not reliably. The first soldier meeting the wire could jump onto the top of it, hopefully depressing it enough for those that followed to get over him; this still took at least one soldier out of action for each line of wire. In World War I, British and Commonwealth forces relied on wire cutters, which proved unable to cope with the heavier gauge German wire.[29] The Bangalore torpedowas adopted by many armies, and continued in use past the end of World War II.[30]
The barbed wire used differed between nations; the German wire was heavier gauge, and British wire cutters, designed for the thinner native product, were unable to cut it.[29]
Geography
The confined, static, and subterranean nature of trench warfare resulted in it developing its own peculiar form of geography. In the forward zone, the conventional transport infrastructure of roads and rail were replaced by the network of trenches and trench railways. The critical advantage that could be gained by holding the high ground meant that minor hills and ridges gained enormous significance. Many slight hills and valleys were so subtle as to have been nameless until the front line encroached upon them. Some hills were named for their height in metres, such as Hill 60. A farmhouse, windmill, quarry, or copse of trees would become the focus of a determined struggle simply because it was the largest identifiable feature. However, it would not take the artillery long to obliterate it, so that thereafter it became just a name on a map.
The battlefield of Flanders presented numerous problems for the practice of trench warfare, especially for the Allied forces, mainly British and Canadians, who were often compelled to occupy the low ground. Heavy shelling quickly destroyed the network of ditches and water channels which had previously drained this low-lying area of Belgium. In most places, the water table was only a metre or so below the surface, meaning that any trench dug in the ground would quickly flood. Consequently, many "trenches" in Flanders were actually above ground and constructed from massive breastworks of sandbags filled with clay. Initially, both the parapet and parados of the trench were built in this way, but a later technique was to dispense with the parados for much of the trench line, thus exposing the rear of the trench to fire from the reserve line in case the front was breached.
In the Alps, trench warfare even stretched onto vertical slopes and deep into the mountains, to heights of 3,900 m (12,800 ft) above sea level. The Ortler had an artillery position on its summit near the front line. The trench-line management and trench profiles had to be adapted to the rough terrain, hard rock, and harsh weather conditions. Many trench systems were constructed within glaciers such as the Adamello-Presanellagroup or the famous city below the ice on the Marmolada in the Dolomites.
Observation
Observing the enemy in trench warfare was difficult, prompting the invention of technology such as the camouflage tree.[31]
No man's land
The space between the opposing trenches was referred to as "no man's land" and varied in width depending on the battlefield. On the Western Front it was typically between 90 and 275 metres (100 and 300 yd), though only 25 metres (30 yd) on Vimy Ridge.
After the German withdrawal to the Hindenburg line in March 1917, no man's land stretched to over a kilometre in places. At the "Quinn's Post" in the cramped confines of the Anzac battlefield at Gallipoli, the opposing trenches were only 15 metres (16 yd) apart and the soldiers in the trenches constantly threw hand grenades at each other. On the Eastern Front and in the Middle East, the areas to be covered were so vast, and the distances from the factories supplying shells, bullets, concrete and barbed wire so great, trench warfare in the West European style often did not occur.
Weaponry
Infantry weapons and machine guns
At the start of the First World War, the standard infantry soldier's primary weapons were the rifle and bayonet; other weapons got less attention. Especially for the British, what hand grenades were issued tended to be few in numbers and less effective. This emphasis began to shift as soon as trench warfare began; militaries rushed improved grenades into mass production, including rifle grenades.
The hand grenade came to be one of the primary infantry weapons of trench warfare. Both sides were quick to raise specialist grenadier groups. The grenade enabled a soldier to engage the enemy without exposing himself to fire, and it did not require precise accuracy to kill or maim. Another benefit was that if a soldier could get close enough to the trenches, enemies hiding in trenches could be attacked. The Germans and Turks were well equipped with grenades from the start of the war, but the British, who had ceased using grenadiers in the 1870s and did not anticipate a siege war, entered the conflict with virtually none, so soldiers had to improvise bombs with whatever was available (see Jam Tin Grenade). By late 1915, the British Mills bombhad entered wide circulation, and by the end of the war 75 million had been used.
Since the troops were often not adequately equipped for trench warfare, improvised weapons were common in the first encounters, such as short wooden clubs and metal maces, spears, hatchets, hammers, entrenching tools, as well as trench knives and brass knuckles. According to the semi-biographical war novel All Quiet on the Western Front, many soldiers preferred to use a sharpened spade as an improvised melee weapon instead of the bayonet, as the bayonet tended to get "stuck" in stabbed opponents, rendering it useless in heated battle. The shorter length also made them easier to use in the confined quarters of the trenches. These tools could then be used to dig in after they had taken a trench. Modern military digging tools are as a rule designed to also function as a melee weapon. As the war progressed, better equipment was issued, and improvised arms were discarded.
A specialised group of fighters called trench sweepers (Nettoyeurs de Tranchées or Zigouilleurs) evolved to fight within the trenches. They cleared surviving enemy personnel from recently overrun trenches and made clandestine raids into enemy trenches to gather intelligence. Volunteers for this dangerous work were often exempted from participation in frontal assaults over open ground and from routine work like filling sandbags, draining trenches, and repairing barbed wire in no-man's land. When allowed to choose their own weapons, many selected grenades, knives and pistols. FN M1900pistols were highly regarded for this work, but never available in adequate quantities. Colt Model 1903 Pocket Hammerless, Savage Model 1907, Star Bonifacio Echeverria and Ruby pistols were widely used.[32]
Various mechanical devices were invented for throwing hand grenades into enemy trenches. The Germans used the Wurfmaschine, a spring-powered device for throwing a hand grenade about 200 m (220 yd).[33] The French responded with the Sauterelle and the British with the Leach Trench Catapult and West Spring Gun which had varying degrees of success and accuracy. By 1916, catapultweapons were largely replaced by rifle grenades and mortars.[34]
The Germans employed Flammenwerfer(flamethrowers) during the war for the first time against the French on 25 June 1915, then against the British 30 July in Hooge. The technology was in its infancy, and use was not very common until the end of 1917 when portability and reliability were improved. It was used in more than 300 documented battles. By 1918, it became a weapon of choice for Stoßtruppen (stormtroopers) with a team of six Pioniere (combat engineers) per squad.
Used by American soldiers in the Western front, the pump action shotgun was a formidable weapon in short range combat, enough so that Germany lodged a formal protest against their use on 14 September 1918, stating "every prisoner found to have in his possession such guns or ammunition belonging thereto forfeits his life", though this threat was apparently never carried out. The U.S. military began to issue models specially modified for combat, called "trench guns", with shorter barrels, higher capacity magazines, no choke, and often heat shields around the barrel, as well as lugs for the M1917 bayonet. Anzac and some British soldiers were also known to use sawn-off shotguns in trench raids, because of their portability, effectiveness at close range, and ease of use in the confines of a trench. This practice was not officially sanctioned, and the shotguns used were invariably modified sporting guns.
The Germans embraced the machine gun from the outset—in 1904, sixteen units were equipped with the 'Maschinengewehr'—and the machine gun crews were the elite infantry units; these units were attached to Jaeger (light infantry) battalions. By 1914, British infantry units were armed with two Vickers machine guns per battalion; the Germans had six per battalion, and the Russians eight.[35] It would not be until 1917 that every infantry unit of the American forces carried at least one machine gun.[36] After 1915, the Maschinengewehr 08 was the standard issue German machine gun; its number "08/15" entered the German language as idiomatic for "dead plain". At Gallipoli and in Palestine the Turks provided the infantry, but it was usually Germans who manned the machine guns.
The British High Command were less enthusiastic about machine guns, supposedly considering the weapon too "unsporting" and encouraging defensive fighting; and they lagged behind the Germans in adopting it. Field Marshal Sir Douglas Haig is quoted as saying in 1915, "The machine gun is a much overrated weapon; two per battalion is more than sufficient".[37] The defensive firepower of the machine gun was exemplified during the first day of the Battle of the Somme when 60,000 British soldiers were rendered casualties, "the great majority lost under withering machine gun fire".[38] In 1915 the Machine Gun Corps was formed to train and provide sufficient heavy machine gun teams.
It was the Canadians that made the best practice, pioneering area denial and indirect fire (soon adopted by all Allied armies) under the guidance of former French Army Reserve officer Major General Raymond Brutinel. Minutes before the attack on Vimy Ridge the Canadians thickened the artillery barrage by aiming machine guns indirectly to deliver plunging fire on the Germans. They also significantly increased the number of machine guns per battalion. To match demand, production of the Vickers machine gun was contracted to firms in the United States. By 1917, every company in the British forces were also equipped with four Lewis light machine guns, which significantly enhanced their firepower.
The heavy machine gun was a specialist weapon, and in a static trench system was employed in a scientific manner, with carefully calculated fields of fire, so that at a moment's notice an accurate burst could be fired at the enemy's parapet or a break in the wire. Equally it could be used as light artillery in bombarding distant trenches. Heavy machine guns required teams of up to eight men to move them, maintain them, and keep them supplied with ammunition. This made them impractical for offensive manoeuvres, contributing to the stalemate on the Western Front.
One machine gun nest was theoretically able to mow down hundreds of enemies charging in the open through no man's land. However, while WWI machine guns were able to shoot hundreds of rounds per minute in theory, they were still prone to overheating and jamming, which often necessitated firing in short bursts.[39] However, their potential was increased significantly when emplaced behind multiple lines of barbed wire to slow any advancing enemy.
In 1917 and 1918, new types of weapons were fielded. They changed the face of warfare tactics and were later employed during World War II.
The French introduced the CSRG 1915 Chauchat during Spring 1916 around the concept of "walking fire", employed in 1918 when 250,000 weapons were fielded. More than 80,000 of the best shooters received the semi-automatic RSC 1917 rifle, allowing them to rapid fire at waves of attacking soldiers. Firing ports were installed in the newly arrived Renault FT tanks.
The French Army fielded a ground version of the Hotchkiss Canon de 37 mm used by the French Navy. It was primarily used to destroy German machine gun nests and concrete reinforced pillboxes with high explosive and armour-piercing rounds.
A new type of machine gun was introduced in 1916. Initially an aircraft weapon, the Bergmann LMG 15 was modified for ground use,[citation needed] with the later dedicated ground version being the LMG 15 n. A. It was used as an infantry weapon on all European and Middle Eastern fronts until the end of World War I. It later inspired the MG 30 and the MG 34 as well as the concept of the general-purpose machine gun.[citation needed]
What became known as the submachine gunhad its genesis in World War I, developed around the concepts of infiltration and fire and movement, specifically to clear trenches of enemy soldiers when engagements were unlikely to occur beyond a range of a few feet. The MP 18 was the first practical submachine gun used in combat. It was fielded in 1918 by the German Army as the primary weapon of the stormtroopers – assault groups that specialised in trench combat. Around the same time, the Italians had developed the Beretta M1918 submachine gun, based on a design from earlier in the war.
Artillery
Artillery dominated the battlefields of trench warfare. An infantry attack was rarely successful if it advanced beyond the range of its supporting artillery. In addition to bombarding the enemy infantry in the trenches, the artillery could be used to precede infantry advances with a creeping barrage, or engage in counter-battery duels to try to destroy the enemy's guns. Artillery mainly fired fragmentation, high-explosive, shrapnel or, later in the war, gas shells. The British experimented with firing thermiteincendiary shells, to set trees and ruins alight. However, all armies experienced shell shortages during the first year or two of World War I, due to underestimating their usage in intensive combat. This knowledge had been gained by the combatant nations in the Russo-Japanese War, when daily artillery fire consumed ten times more than daily factory output, but had not been applied.[40]
Artillery pieces were of two types: infantry support guns and howitzers. Guns fired high-velocity shells over a flat trajectory and were often used to deliver fragmentation and to cut barbed wire. Howitzers lofted the shell over a high trajectory so it plunged into the ground. The largest calibers were usually howitzers. The German 420 mm (17 in) howitzer weighed 20 tons and could fire a one-ton shell over 10 km (6.2 mi). A critical feature of period artillery pieces was the hydraulic recoil mechanism, which meant the gun did not need to be re-aimed after each shot, permitting a tremendous increase in rate of fire.
Initially each gun would need to register its aim on a known target, in view of an observer, in order to fire with precision during a battle. The process of gun registration would often alert the enemy an attack was being planned. Towards the end of 1917, artillery techniques were developed enabling fire to be delivered accurately without registration on the battlefield—the gun registration was done behind the lines then the pre-registered guns were brought up to the front for a surprise attack.
Mortars, which lobbed a shell in a high arc over a relatively short distance, were widely used in trench fighting for harassing the forward trenches, for cutting wire in preparation for a raid or attack, and for destroying dugouts, saps and other entrenchments. In 1914, the British fired a total of 545 mortar shells; in 1916, they fired over 6,500,000. Similarly, howitzers, which fire on a more direct arc than mortars, raised in number from over 1,000 shells in 1914, to over 4,500,000 in 1916. The smaller numerical difference in mortar rounds, as opposed to howitzer rounds, is presumed by many to be related to the expanded costs of manufacturing the larger and more resource intensive howitzer rounds.
The main British mortar was the Stokes, a precursor of the modern mortar. It was a light mortar, simple in operation, and capable of a rapid rate of fire by virtue of the propellant cartridge being attached to the base shell. To fire the Stokes mortar, the round was simply dropped into the tube, where the percussion cartridge was detonated when it struck the firing pin at the bottom of the barrel, thus being launched. The Germans used a range of mortars. The smallest were grenade-throwers ('Granatenwerfer') which fired the stick grenades which were commonly used. Their medium trench-mortars were called mine-throwers ('Minenwerfer'). The heavy mortarwas called the 'Ladungswerfer', which threw "aerial torpedoes", containing a 200 lb (91 kg) charge to a range of 1,000 yd (910 m). The flight of the missile was so slow and leisurely that men on the receiving end could make some attempt to seek shelter.
Mortars had certain advantages over artillery such as being much more portable and the ability to fire without leaving the relative safety of trenches. Moreover, mortars were able to fire directly into the trenches, which was hard to do with artillery.[41]
Strategy and tactics
The fundamental strategy of trench warfare in World War I was to defend one's own position strongly while trying to achieve a breakthrough into the enemy's rear. The effect was to end up in attrition; the process of progressively grinding down the opposition's resources until, ultimately, they are no longer able to wage war. This did not prevent the ambitious commander from pursuing the strategy of annihilation—the ideal of an offensive battle which produces victory in one decisive engagement.
The Commander in Chief of the British forces during most of World War I, General Douglas Haig, was constantly seeking a "breakthrough" which could then be exploited with cavalry divisions. His major trench offensives—the Somme in 1916 and Flanders in 1917—were conceived as breakthrough battles but both degenerated into costly attrition. The Germans actively pursued a strategy of attrition in the Battle of Verdun, the sole purpose of which was to "bleed the French Army white". At the same time the Allies needed to mount offensives in order to draw attention away from other hard-pressed areas of the line.[42]
The popular image of a trench assault is of a wave of soldiers, bayonets fixed, going "over the top" and marching in a line across no man's land into a hail of enemy fire. This was the standard method early in the war; it was rarely successful. More common was an attack at night from an advanced post in no man's land, having cut the barbed wire beforehand. In 1915, the Germans innovated with infiltration tactics where small groups of highly trained and well-equipped troops would attack vulnerable points and bypass strong points, driving deep into the rear areas. The distance they could advance was still limited by their ability to supply and communicate.
The role of artillery in an infantry attack was twofold. The first aim of a bombardment was to prepare the ground for an infantry assault, killing or demoralising the enemy garrison and destroying their defences. The duration of these initial bombardments varied, from seconds to days. Artillery bombardments prior to infantry assaults were often ineffective at destroying enemy defences, only serving to provide advance notice of an attack. The British bombardment that began the Battle of the Somme lasted eight days but did little damage to either the German barbed wire or their deep dug-outs, where defenders were able to wait out the bombardment in relative safety.[43]
Once the guns stopped, the defenders had time to emerge and were usually ready for the attacking infantry. The second aim was to protect the attacking infantry by providing an impenetrable "barrage" or curtain of shells to prevent an enemy counter-attack. The first attempt at sophistication was the "lifting barrage" where the first objective of an attack was intensely bombarded for a period before the entire barrage "lifted" to fall on a second objective farther back. However, this usually expected too much of the infantry, and the usual outcome was that the barrage would outpace the attackers, leaving them without protection.
This resulted in the use of the "creeping barrage" which would lift more frequently but in smaller steps, sweeping the ground ahead and moving so slowly that the attackers could usually follow closely behind it. This became the standard method of attack from late 1916 onward. The main benefit of the barrage was suppression of the enemy rather than to cause casualties or material damage.
Capturing the objective was half the battle, but the battle was won only if the objective was held. The attacking force would have to advance with not only the weapons required to capture a trench but also the tools—sandbags, picks and shovels, barbed wire—to fortify and defend from counter-attack. A successful advance would take the attackers beyond the range of their own field artillery, making them vulnerable, and it took time to move guns up over broken ground. The Germans placed great emphasis on immediately counter-attacking to regain lost ground. This strategy cost them dearly in 1917 when the British started to limit their advances so as to be able to meet the anticipated counter-attack from a position of strength. Part of the British artillery was positioned close behind the original start line and took no part in the initial bombardment, so as to be ready to support later phases of the operation while other guns were moved up.
The Germans were the first to apply the concept of "defence in depth", where the front-line zone was hundreds of metres deep and contained a series of redoubts rather than a continuous trench. Each redoubt could provide supporting fire to its neighbours, and while the attackers had freedom of movement between the redoubts, they would be subjected to withering enfilade fire. They were also more willing than their opponents to make a strategic withdrawal to a superior prepared defensive position.[citation needed] The British eventually adopted a similar approach, but it was incompletely implemented when the Germans launched the 1918 Spring Offensive and proved disastrously ineffective. France, by contrast, relied on artillery and reserves, not entrenchment.
Life in the trenches
An individual unit's time in a front-line trench was usually brief; from as little as one day to as much as two weeks at a time before being relieved. The 31st Australian Battalion once spent 53 days in the line at Villers-Bretonneux, but such a duration was a rare exception. The 10th Battalion, CEF, averaged front line tours of six days in 1915 and 1916.[44]The units who manned the front line trenches the longest were the Portuguese Expeditionary Corps from Portugal stationed in Northern France; unlike the other allies the Portuguese couldn't rotate units from the front lines due to lack of reinforcements sent from Portugal, nor could they replace the depleted units that lost manpower due to the war of attrition. With this rate of casualties and no reinforcements forthcoming, most of the men were denied leave and had to serve long periods in the trenches with some units spending up to six consecutive months in the front line with little to no leave during that time.[45]
On an individual level, a typical British soldier's year could be divided as follows:
- 15% front line
- 10% support line
- 30% reserve line
- 20% rest
- 25% other (hospital, travelling, leave, training courses, etc.)
Even when in the front line, the typical battalion would be called upon to engage in fighting only a handful of times a year; making an attack, defending against an attack or participating in a raid. The frequency of combat would increase for the units of the "elite" fighting divisions; on the Allied side, these were the British regular divisions, the Canadian Corps, the French XX Corps, and the Anzacs.
Some sectors of the front saw little activity throughout the war, making life in the trenches comparatively easy. When the I Anzac Corpsfirst arrived in France in April 1916 after the evacuation of Gallipoli, they were sent to a relatively peaceful sector south of Armentières to "acclimatise". In contrast, some other sectors were in a perpetual state of violent activity. On the Western Front, Ypreswas invariably hellish, especially for the British in the exposed, overlooked salient. However, even quiet sectors amassed daily casualties through sniper fire, artillery, disease, and poison gas. In the first six months of 1916, before the launch of the Somme Offensive, the British did not engage in any significant battles on their sector of the Western Front and yet suffered 107,776 casualties. Only 1 in 2 men would return alive and unwounded from the trenches.[citation needed]
A sector of the front would be allocated to an army corps, usually comprising three divisions. Two divisions would occupy adjacent sections of the front, and the third would be in rest to the rear. This breakdown of duty would continue down through the army structure, so that within each front-line division, typically comprising three infantry brigades (regiments for the Germans), two brigades would occupy the front and the third would be in reserve. Within each front-line brigade, typically comprising four battalions, two battalions would occupy the front with two in reserve, and so on for companies and platoons. The lower down the structure this division of duty proceeded, the more frequently the units would rotate from front-line duty to support or reserve.
During the day, snipers and artillery observersin balloons made movement perilous, so the trenches were mostly quiet. It was during these daytime hours that the soldiers would amuse themselves with trench magazines. Because of the peril associated with daytime activities, trenches were busiest at night when the cover of darkness allowed movement of troops and supplies, the maintenance and expansion of the barbed wire and trench system, and reconnaissance of the enemy's defenses. Sentries in listening posts out in no man's land would try to detect enemy patrols and working parties, or indications that an attack was being prepared.
Pioneered by the Princess Patricia's Canadian Light Infantry in February 1915,[46] trench raidswere carried out in order to capture prisoners and "booty"—letters and other documents to provide intelligence about the unit occupying the opposing trenches. As the war progressed, raiding became part of the general British policy, the intention being to maintain the fighting spirit of the troops and to deny no man's land to the Germans. As well, they were intended to compel the enemy to reinforce, which exposed their troops to artillery fire.[46]
Such dominance was achieved at a high cost when the enemy replied with their own artillery,[46] and a post-war British analysis concluded the benefits were probably not worth the cost. Early in the war, surprise raids would be mounted, particularly by the Canadians, but increased vigilance made achieving surprise difficult as the war progressed. By 1916, raids were carefully planned exercises in combined arms and involved close co-operation between infantry and artillery.
A raid would begin with an intense artillery bombardment designed to drive off or kill the front-trench garrison and cut the barbed wire. Then the bombardment would shift to form a "box barrage", or cordon, around a section of the front line to prevent a counter-attack intercepting the raid. However, the bombardment also had the effect of notifying the enemy of the location of the planned attack, thus allowing reinforcements to be called in from wider sectors.